Apparatus for stencil decorating



u y 8, 1939. J. c. SMITH 2,166,269

APPARATUS FOR STENCIL DECORATING Fil ed June 28, 1957 2 Sheets-Sheet 1 1 f6 '1 6 .imHIHH I 28 I? 29 1/ I 55 25 I: |||I n|m '26 INVENTOR M n I a I "WMKW 74 g4 {\TTORNEYJ July 18, 1939. .J. c. SMITH AFPARATUS FOR STENCIL DECQRATING Filed June 28, 1957 2 Sheets-Sheet 2 INV ENT OR. dfl 'd M Wmfl WATTORNEY or curved irregularly otherwise.

Patented July 18, 1939 PATENT OFFICE 2,166,269 7 APPARATUS FOR, STENCIL DECORATING John E. Smith, Beaver, Pa, asslgnor to Solar Laboratories, Beaver, Pin, a corporation of Pennsylvania Application June 28, 1937, Serial No. 150,790

a Claims.

This invention relates to the art of applying decorations to articles of manufacture such as urns, vases, pottery and similar ware made of metal, glass, resinous, or ceramic materials, by a method which has become known generally as the silk screen" process. In this process, the decorative design is constituted by a plurality of related perforations, in a screen or membrane made of a foraminous material such as silk, tulle, or perforated metal. The screen, which is rendered impervious in the areas bounding the design perforations, is mounted in a frame, then is brought into relationship with the surface to be decorated, and ink, paint, or some suitable coloring matter is pressed through the perforations 'constituting the design in the screen, onto the surface of the ware by means of an applicator or squeegee. The present invention is an improvement in the silk screen process, and is useful particularly for decorating articles which are irregular in shape or curved convexly in one or more directions.

'It has been the object to provide a method for obtaining sharp delineations of the design indicia.

applied to the surface of the ware from the screen whether the article be round, oval, globular The drawings illustrate one machine adapted to the practice of the method by means of which this objective is accomplished.

Briefly, it is' the concept of the present invention to mount the screen for rocking movement in relation to the surface of the ware, which is held, as in a chuck, in stationary position, and to relate the feed of the screen across the surface of the ware during its rocking movement, to the linear rate of movement of a squeegee traveling upon the surface of the screen. Through the rocking movement, successive portions of the screen respectively, and serially are brought into substantially tangential contact with the surface of the ware. The line (or localized area) of contact ofrthe screen with the ware progresses the length of the screen as it is rocked about the periphery of the article, while the squeegee, being moved in relation to the rate of movement of the contact area, feeds the ink or color substance through the perforations of the screen at the portions of the screen then in contact with the 'ware, for application of the design thereto.

stretched tautly. While this mounting is satis- "factory when the surface of the ware is relatively flat, particularly in directions transverse the screen, it is not practical when the surface in the transverse is a curved one, as for instance, in a teapot curving inwardly toward the base. In the practice of the present invention, the screen is mounted in a frame suiiiciently loosely or resiliently to permit the membrane to assume the curvature or configuration of the ware under the influence of the squeegee, but sufliciently tightly to permit the screen to be withdrawn from the surface upon the rocking movement of the screen, after the color medium has been impressed. The squeegee may be a resilient applicator, and its surface, if desired, may be shaped to conform to the configurations of the ware.

For the purpose of illustrating the invention the improvements are disclosed in relation to the decoration of the sides of a ceramic teapot, since this is the type of work which it has been difficult to decorate by the methods known in the. past. Those skilled in the art readily will understand the variety of uses to which the invention is adapted, for instance, in the decoration of cups, bowls, vases, pots, and similar pieces, both large and small in size. The concept of relating the' feed of successive portions of the stencil screen to undecorated portions of the surfaceof the ware with a linear rate of movement of the squeegee to synchronize the two, is adapted to the decoration of articles not having surfaces which are curved irregularly, even though the resilient mounting of the stencil in the frame be not employed.

In the drawings illustrating a machine of the invention:

Figure 1 is a side elevation of the stenciling machine of the present invention.

Figure 2 is a top plan view of the same.

Figure 3 is a section on line 3, 3 of Figure 1 centrally of the machine.

Figure 4 is an enlarged fragmentary view detailing the disposition of the stencil screen and squeegee with relation to the article being decorated prior to the decorating operation.

Figure 5 is a view similar to Figure 4 illustrating the relationship of the parts as the stenciling operation progresses.

The mechanism in general comprises suitable supports l0, constituting a chuck for the work, a stencil screen Ii, disposed above the work and in operating connection with a bell crank lever I2 pivoted on a bracket l3 fastened to the frame I 4 of the machine. i V.

The frame H of the machine includes two arcuate side members l5 and I6 mounted on a base I1, between which the work supports ID are mounted. The upper edge of each ofthe side members II and ll forms a shoulder l8 providing a track on which the stencil frame ll rests in rocking engagement. The engagement of the frame of the stencil with the shoulders disposes the stencil with proper operating clearance above the surface of the work and the arc described by the shoulders is approximately the same as the arc of the convex side of the work, as indicated at 2|.

The bearing bracket if, on which the bell crank lever l2 pivots, is located on the same center from which the arc of the side members l5 and I5 and shoulders ll are described. Therefore, a point on this lever adjacent to the line of the arcuate shoulders describes an identical arc when the lever is swung in its operating ath.

p A scraper or squeegee 2| is attached to the bell crank lever by means of a hinge 22 to be used in conjunction with the stencil in printing the design. The squeegee is located on the lever at a point to dispose its wiping edge 23 in a plane normal to the plane of the screen and substantially in line with the arc of the guideway or track of the stencil for traversing the surface of the stencil.

The stencil is in connection with the bell crank lever by means of a link 24 pivoted between an arm 25 of the lever and the frame of the stencil. The proportionate length of the arm and the main 'arm of the bell crank lever is such that the movement of the lever rocks the stencil (which is at all times a fixed distance from the work) a proper amount to dispose it at right angles to the squeegee throughout the entire range of travel as shown in Figures 4' and 5. The squeegee is normally kept clear of the stencil surface by means of the spring 26 tensioned between the squeegee and the lever. A knob 21 is provided on the squeegee to be grasped 'by the operator for applying pressure.

In order to provide a positive ratio between the swinging movement of the lever and the rocking of the stencil frame, and to prevent slippage, the frame is provided with a rack 25, on its under surface, in mesh with an arcuate rack 29 mounted on the shoulders in insets provided for this purpose. The arcuate racks are of the same radius as that of the stencil guldeways, and the contact between the guideways and frame of the stencil determines correct meshing of the two sets of racks for proper operating engagement. A pair of weights 20 and 2| is attached on opposite ends of the stencil frame in order to keep the stencil firmly in place on the frames.

The stencil frame rocks on the shoulders of the guideway, and the squeegee is always at a point on the stencil which is tangent to the work surface (see Figures 4 and 5).

The arrangement of the parts is such that there is a. positive coaction between the movement of the squeegee and the angle of the stencil, the stencil frame being arranged to rock according to the movement of the bell crank lever, so that the stencil frame is always at right angles to the main arm of the bell crank lever. The squeegee mounted adjacent the main arm of the bell crank lever is therefore disposed parallel therewith. Consequently, the squeegee is always both at right angles to the stencil and coinciding with the point of tangency of the work surface and the stencil. Longitudinal motion of the stencil with respect to the guideways is preventment by lifting from the machine.

ed by the meshing of the rack teeth between the two parts, and transverse motion is prevented by the side members on the outsides of the shoulders. Thus the stencil frame is restrained against any motion other than that effected by the bell crank lever.

Since there is a clearance between the work surface and the stencil, a slight pressure is necessary on the squeegee to contact the work. The wedged shaped wiping edge 22 of the squeegee, preferably, is arched slightly to conform substantially to the curvature of the work and, being of soft rubber, readily adapts itself to variations in the convex outline of the work surface. The stencil is mounted sufficiently loosely in its frame to permit stretching, and it conforms to the curvature of the work surface transverse the path of travel (see Figure 3). This assures a stenciling path of substantial width; providing proper contact for printing designs of considerable width in one operation.

From the foregoing it may be seen that the stencil is presented to the work surface in a line contact, the stencil being spaced from the work and forced into contact only along the line of the wiping edge of the stencil. The deflection of the stencil from its normal plane along this line provides clearance on all sides surrounding the design, thus aiding in procuring'a clean-cut print, permitting the stencil to move out of contact with the work in a direct line as the squeegee traverses its path.

In operating the machine, pigment is applied to the stencil and the operator moves the main arm of thebell crank lever with one hand and with the other bears down on the squeegee to contact the work surface. The pigment, indicated at 32 on Figures 4 and 5, is scraped across the face of the stencil and is forced through at the design openings 33 and deposited on the surface of the work as at 34. Stops 35 are provided at one end of the shoulders to limit the range of movement.

The stencils may be readily removed from the machine at any time for cleaning or replace- The sleeve 36 on the frame of the stencil in which the link connection 24 pivots, is fastened to the stencil frame and provides a slip-on engagement with the link to provide easy removal.

Having described my invention, I claim:

1. An apparatus for decorating ware having convex surfaces, which comprises, means for holding the ware, a screen carried in a frame, means for rocking the screen serially to feed successive portions of the screen into contact with the success ve portions of the surface of the ware, a squeegee positioned for traverse of the screen as it is rocked, and means relating the rate of traverse of the squeegee on the screen with the rate of rocking of the "screen upon the ware, whereby ink applied to the screen is fed therethrough as the screen contacts successive portions of the ware.

2. Stenciling apparatus, comprising, a stencil screen including a frame therefor, means for holding a body presenting a convex surface in position for tangential contact of the screen with said surface, arcuate means supporting the frame of the screen and guiding it for rocking movement about the said surface, a squeegee positioned to impress the screen against the surface of the body, and means for synchronizing the rate of movement of the squeegee on the screen, with the rate of movement of the screen about the surface when it is rocked, the screen being adapted to yield from the plane of its frame under pressure of the squeegee into contact with the convex surface;

3..Apparatus for stenciling articles presenting convex surfaces, comprising, a chuck to hold the articles in stationary position, a stencil screen positioned adjacent the article in contact with a surface thereof to be stenciled, a track member on which the screen is rocked about said surface, a squeegee contacting the screen on the side opposite the said surface, and means for moving the squeegee over the screen as the screen rocks about the surface, whereby the squeegee is adapted to feed coloring material through the screen as the screen contacts successive portions of said surface.

4. Apparatus for stenciling articles presenting convex surfaces; comprising, a chuck to hold one of said articles in stationary position. a stencil screen mounted for rocking movement about the surface to be ,stcncilcd, a squeegee mounted in contact with a surface of the screen on the side opposite said article, and means for maintaining the angular relationship of the squeegee to the screen as the screen is rocked about the surface to bestencile'd.

5. In a stenciling apparatus, a stencil screen, a

squeegee adapted to impel coloring material through the screen, a chuck adapted to support an object to be stenciled in contact with the screen on the side opposite the stencil, means for rocking the screen about an article positioned in the chuck, and means for moving the squeegee with said surface.

7. Apparatus for stenciling articles presenting convex surfaces... comprising, a stencil screen, means for holding the article in stationary position adjacent the screen, a squeegee for impelling-coioring matter through the screen onto the surface of the article, means for rocking the screen and means for coordinating the point of contact of the squeegee and the screen, withthe point of contact of the screen and thesurface of the article during rocking movement of the screen.

8. Apparatus for stenciling an article presenting a convex surface to be decorated, which comprises, means for supporting the article in stationary position, a rockable stencil screen posi- 'tioned adjacent the surface of the article to be decorated, a squeegee movable over the surface of the screen as it is rocked, and means for coordinating the point of contact of the squeegee with the screen, and the point of contact of the surface of the screen with the article.

7 JOHN 0. SMITH. 

